This section introduces aspects that may help facilitate a better understanding of the invention(s). Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art.
The abbreviations and terms appearing in the description and drawings are defined as below.    3GPP Third Generation Partnership Project    ABS Almost Blank Subframe    BS Base Station    DL Downlink    eNB E-UTRAN NodeB, Base Station in E-UTRAN    E-UTRAN Evolved UTRAN    FDD Frequency Division Duplex    IE Information Element    LTE-A Long Term Evolution-Advanced    TDD Time Division Duplex    UE User Equipment    UL Uplink
Wireless communication systems include a network of devices for providing wireless connectivity to wireless-enabled devices including mobile units, smart phones, tablet devices, laptops, desktops, and other types of user equipment. The network access devices include base stations, base station routers, access points, e-node-Bs (eNBs), and the like. The entities within the wireless communication system generally conform to standards and/or protocols that facilitate communication over the air interface. For example, wireless communication systems are currently being developed that operate according to the Long Term Evolution (LTE) standards and/or protocols defined by the Third Generation Partnership Project (3GPP, 3GPP2). The LTE-Advanced standard supports both frequency division duplexing (FDD) and time division duplexing (TDD). Service providers are expected to implement both types of systems depending on the circumstances of the deployment scenario. The advantages to deploying a TDD system include efficient use of the radio spectrum because TDD uses a single frequency resource and does not require the paired set of frequency resources used to implement FDD.
FIG. 1 shows the FDD frame structure and the TDD frame structure defined in LTE system. As shown in FIG. 1, one radio frame has an overall length of 10 ms.
In FDD frame structure, the frame is divided into a total of 10 subframes, each having a length of 1 ms. The uplink (UL) subframes and the downlink (DL) subframes are transmitted on different frequencies fUL and fDL.
In TDD frame structure, the 10 ms frame comprises two half frames, each 5 ms long. Each half frame is further split into five subframes, each 1 ms long. The subframes may be divided into UL transmission subframe, DL transmission subframe, and special subframe. The special subframes consist of three fields: Downlink Pilot Time Slot (DwPTS), Guard Period (GP), and Uplink Pilot Time Slot (UpPTS).
One of the advantages of using LTE TDD is that it is possible to dynamically change the uplink and downlink ratio and characteristics to meet various load conditions. Motivated by TDD spectrum operator desire to better control interference from co-channel deployments and for traffic adaptation, in LTE-A, the use of dynamic reconfiguration of TDD frame allocation is currently being considered for possible standardization in Release 11.
However, interference between neighbour base stations and/or user equipments may arise due to the dynamic reconfiguration of TDD frame allocation in neighbour base stations. For example, base-station-to-base-station (BS-to-BS) interference occurs when one base station transmits a downlink signal to a user equipment in a subframe while a neighbour base station is attempting to receive an uplink signal from other user equipment during the same subframe. For another example, user-equipment-to-user-equipment (UE-to-UE) interference occurs when one or more user equipment are transmitting uplink signals to a base station in a subframe while other user equipments are trying to receive downlink signals from another base station during the same subframe.
Generally speaking, the UE-to-UE or BS-to-BS interference may occur when different uplink and downlink frame allocations are used in neighbour cells, for example, when these neighbour cells are from different operators, or the neighbour cells belong to different network (e.g., one is LTE-FDD, the other is LTE-TDD). The UE-to-UE or BS-to-BS interference may also occur in future systems, e.g., device to device communication system.